I remember you said something in Chapter 46 about how Rain is basically your alter-ego of sorts...and then something about Dissociative Identity Disorder in chapter 54.

Maybe Rain's one of your other personalities and Rain wrote that poem? Where do you keep the stuff you write for fictionpress? (Like with me I keep all my fictionpress stuff in a well hidden folder on the computer) Check wherever it is you keep your writing, because maybe you technically did write those poems.